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For most providers, like Protonmail, the decryption password is the same as your login password. I'm curious what scenario you see allowing someone other than t

by BCM43 9y ago

For most providers, like Protonmail, the decryption password is the same as your login password. I'm curious what scenario you see allowing someone other than the provider to get access to your mailbox but not also your decryption key.

dboreham 9y ago
That could happen via a breach of the provider's servers, or through dumpster diving for a discarded drive that the provider didn't properly wipe (in the case the data wasn't also encrypted at rest).
- brongondwana 9y ago
  Email at FastMail is encrypted at rest in this sense (full drive encryption). It's not encrypted with a separate password per-user. We don't see any security benefits there, given that every user logs in almost every day, and if they have linked a device (many of our users use IMAP from mobile clients) they will connect and sync every time there's an update. Which changes the vector to "hack server, passively monitor for a couple of hours, gain access". The logical backflips and single-minded security outlook required to consider that significantly different from "hack server, gain access" are the kind of security theater we studiously avoid. Full disk encryption is a clear win with no significant downsides (slightly higher CPU consumption). Per-user encryption while still providing a full email service is not a clear win, and it has significantly higher downsides.
whyagaindavid 9y ago
For proton mail you could set different passwords for decryption and login
gst 9y ago
ProtonMail doesn't have access to the decryption password as it is not transferred to the server. Instead the client sends a password that's derived from it: https://protonmail.com/blog/encrypted_email_authentication/ https://protonmail.com/blog/encrypted_email_authentication/
- carussell 9y ago
  The "client" is a webpage that exists as one of many assets delivered to your browser by the ProtonMail webmail server. The server has access to the password at any time if it wants it.
arghwhat 9y ago
The decryption password is not the same as the login password for ProtonMail. Logging in at minimum requires entering your username, your login password, and your mailbox password. The result is security at rest, which fastmail does not have. ProtonMail's web app is open-source, and can be deployed locally if you wish to remove the chance of an evil app deployment. If you use the official deployment, an evil update can obtain your mailbox password, in which case the the adversary (that is, the one capable of pushing the update) observe a security level equivalent to if security at rest was not implemented. However, even in this case, the data on the mail-servers is still protected from everyone else, so while a single adversary has observed a security level identical to that of fastmail (i.e. no security at rest), everyone else still observes a secured mailbox. Not having security at rest is, in my opinion, dangerous.
- terraforming 9y ago
  That's wrong. You no longer need a third password in protonmail. All you need to have, in order to login, is the username and a password. If you've 2FA enabled, you need the 2FA code of-course.
  - arghwhat 9y ago
    I think you mean second password rather than third, but as a user of ProtonMail, I need one username, two passwords and one 2FA token to get in, with only login username/password being kept in a password manager (and all password managers get confused by multiple passwords, so I couldn't keep them all even if I changed my mind and wanted to). ProtonMail may have the option (I am not aware of this) to have login password and mailbox password set the same (and not prompt you twice if this is the case), but they are still separate passwords. You, as user, control whether you want them to be the same or not. If you chose this, the application then has an option for convenience to use the same input for both tasks. This is opposed to a service where they are always the same, so that the password send to the backend is the same used to decrypt your data.
brightball 9y ago
That's definitely not the default with Protonmail. They'll allow you to change it to that if you really want to though. On mine at least, proton prompts me for username and password, then 2 factor auth, then the decryption code.
- arosier 9y ago
  One password is now the default for new ProtonMail accounts. For accounts that were created before this authentication was released, you will remain on 2 password until you update it in your settings.

by BCM43 9y ago

dboreham 9y ago

That could happen via a breach of the provider's servers, or through dumpster diving for a discarded drive that the provider didn't properly wipe (in the case the data wasn't also encrypted at rest).

brongondwana 9y ago
Email at FastMail is encrypted at rest in this sense (full drive encryption). It's not encrypted with a separate password per-user. We don't see any security benefits there, given that every user logs in almost every day, and if they have linked a device (many of our users use IMAP from mobile clients) they will connect and sync every time there's an update. Which changes the vector to "hack server, passively monitor for a couple of hours, gain access". The logical backflips and single-minded security outlook required to consider that significantly different from "hack server, gain access" are the kind of security theater we studiously avoid. Full disk encryption is a clear win with no significant downsides (slightly higher CPU consumption). Per-user encryption while still providing a full email service is not a clear win, and it has significantly higher downsides.

whyagaindavid 9y ago

For proton mail you could set different passwords for decryption and login

gst 9y ago

ProtonMail doesn't have access to the decryption password as it is not transferred to the server. Instead the client sends a password that's derived from it: https://protonmail.com/blog/encrypted_email_authentication/ https://protonmail.com/blog/encrypted_email_authentication/

carussell 9y ago
The "client" is a webpage that exists as one of many assets delivered to your browser by the ProtonMail webmail server. The server has access to the password at any time if it wants it.

arghwhat 9y ago

The decryption password is not the same as the login password for ProtonMail. Logging in at minimum requires entering your username, your login password, and your mailbox password. The result is security at rest, which fastmail does not have. ProtonMail's web app is open-source, and can be deployed locally if you wish to remove the chance of an evil app deployment. If you use the official deployment, an evil update can obtain your mailbox password, in which case the the adversary (that is, the one capable of pushing the update) observe a security level equivalent to if security at rest was not implemented. However, even in this case, the data on the mail-servers is still protected from everyone else, so while a single adversary has observed a security level identical to that of fastmail (i.e. no security at rest), everyone else still observes a secured mailbox. Not having security at rest is, in my opinion, dangerous.

terraforming 9y ago
That's wrong. You no longer need a third password in protonmail. All you need to have, in order to login, is the username and a password. If you've 2FA enabled, you need the 2FA code of-course.
- arghwhat 9y ago
  I think you mean second password rather than third, but as a user of ProtonMail, I need one username, two passwords and one 2FA token to get in, with only login username/password being kept in a password manager (and all password managers get confused by multiple passwords, so I couldn't keep them all even if I changed my mind and wanted to). ProtonMail may have the option (I am not aware of this) to have login password and mailbox password set the same (and not prompt you twice if this is the case), but they are still separate passwords. You, as user, control whether you want them to be the same or not. If you chose this, the application then has an option for convenience to use the same input for both tasks. This is opposed to a service where they are always the same, so that the password send to the backend is the same used to decrypt your data.

brightball 9y ago

That's definitely not the default with Protonmail. They'll allow you to change it to that if you really want to though. On mine at least, proton prompts me for username and password, then 2 factor auth, then the decryption code.

arosier 9y ago
One password is now the default for new ProtonMail accounts. For accounts that were created before this authentication was released, you will remain on 2 password until you update it in your settings.